E-cigarettes are often touted as a safer alternative to traditional cigarettes, but according to a study released by the Harvard School of Public Health, they may just pose a different threat than their nicotine-filled counterparts.

According to the study, 75 percent of flavored e-cigarettes and their refill liquids were found to contain Diacetyl, “a flavoring chemical linked to cases of severe respiratory disease” such as the incurable condition called “Popcorn Lung.”